The instant invention concerns a motor vehicle comprising:
a first engine constituted by an internal combustion engine for producing a mechanical power, PA1 speed slaving means comprising first measurement means coupled to said first engine for providing a first measurement signal representative of the rotation speed of said first engine and responding to a desired speed signal representative of a desired rotation speed for slaving said rotation speed of said first engine to said desired rotation speed, PA1 a control device comprising a control member able to be actuated by a driver of said vehicle and a detector coupled to said control member for providing a first desired power signal representative of the position of said control member and of a first desired power; PA1 a generator mechanically coupled to said first engine for producing a first electric power in response to said mechanical power; PA1 a drive wheel; PA1 a second engine constituted by an electric motor mechanically coupled to said drive wheel, and PA1 regulating means responding to said first electric power for supplying a second electric power to said second engine and responding to said first desired power signal for producing said desired speed signal and for slaving said second electric power to said first desired power. PA1 speed slaving means comprising first measurement means coupled to said first engine for providing a first measurement signal representative of the rotation speed of said first engine and responding to a desired speed signal representative of a desired rotation speed for slaving said rotation speed of said first engine to said desired rotation speed; PA1 a control device comprising a control member able to be actuated by a driver of said vehicle and a detector coupled to said control member for providing a first desired power signal representative of the position of said control member and of a first desired power; PA1 a generator mechanically coupled to said first engine for producing a first electric power in response to said mechanical power; PA1 a drive wheel; PA1 a second engine constituted by an electric motor mechanically coupled to said drive wheel; and PA1 regulating means responding to said first electric power for supplying a second electric power to said second engine and responding to said first desired power signal for producing said desired speed signal and for slaving said second electric power to said first desired power, PA1 and which is characterised in that said vehicle further comprises second measurement means coupled to said second engine for providing a second measurement signal representative of the rotation speed of said second engine; PA1 and in that said regulating means comprise:
A vehicle having the above characteristics, which is often termed a hybrid vehicle, is disclosed in the PCT patent application published under number WO 93/07021.
When a vehicle of this type is used, its internal combustion engine is permanently in operation. The generator driven by this engine thus also permanently provides all the energy consumed by the electric motor which is coupled to the drive wheel of the vehicle, and which will be called a drive motor in the following description.
This feature gives this vehicle the advantage of not having to include a large capacity accumulator battery such as that which, in other known vehicles of the same type, provides at least partially and/or temporarily the electric energy consumed by the drive motor.
The vehicle disclosed in patent application WO 93/07021 mentioned above, comprises a control circuit which slaves the electric power supplied to the drive motor to a variable desired power determined by the position of an accelerator pedal.
When the driver of the vehicle modifies the position of the accelerator pedal to increase the power supplied to the drive motor, for the purpose, for example, of increasing the speed of this vehicle, the regulating circuit determines a new desired power corresponding to the new position of the accelerator pedal and a new desired rotation speed which is that at which the internal combustion engine of the vehicle must rotate to provide a mechanical power equal, except for the losses, to the above-mentioned desired power while only consuming the smallest possible amount of fuel.
Initially, the regulating circuit does not however modify the electric power supplied by the generator to the drive motor, but only acts upon the internal combustion engine so that the mechanical power provided by the latter increases. Since this mechanical power is now greater than the electric power provided by the generator, the rotation speed of the internal combustion engine increases.
At the moment when this internal combustion engine rotation speed reaches its new desired value, and only at this moment, the regulating circuit increases the electric power supplied to the drive motor to its new desired value. As this electric power is now equal, again except for the losses, to the mechanical power provided by the internal combustion engine, the rotation speed of the latter stabilises at the new desired speed.
It can be seen that in such a case, the electric power supplied to the drive motor does not immediately increase when the driver of the vehicle moves the accelerator pedal to its new position, but only after a certain period of time which may amount to several seconds, which is very unpleasant for the driver of the vehicle and may even be dangerous.
A known vehicle such as the one which has been described above also has the disadvantage that, when its driver rapidly changes the position of its accelerator pedal by a significant amount when it is at rest or moving slowly, the regulating circuit supplies to the drive motor all the electric power corresponding to the new position of the accelerator pedal as soon as the internal combustion engine has reached its new desired speed, as has been described above.
At this moment, the drive motor is still at rest or is rotating only slowly. The current which it absorbs can thus be very high and have an intensity several times greater than that of the current absorbed by this drive motor when it rotates at its maximum speed while providing its maximum mechanical power.
The various electronic components of the regulating circuit which are traversed by the current absorbed by the drive motor must therefore be so dimensioned that they are capable of withstanding this very high current without damage, even if the circumstances in which this very high current passes in these components occur only relatively rarely. These components are thus costly, and their price unfavourably affects that of the regulating circuit.